Does clear cell carcinoma of stomach exist? Clinicopathological and prognostic significance of clear cell changes in gastric adenocarcinomas.

AIMS: In contrast to clear cell carcinomas developing in other organs (e.g. ovary and uterus), gastric adenocarcinomas with clear cell features are not well characterized. METHODS AND RESULTS: We evaluated a series of 762 gastric adenocarcinomas for the presence of clear cell changes; and investigated the nature of the changes using several histochemical and immunohistochemical markers, their association with various clinicopathological features, and their prognostic significance. Clear cell changes were observed in 8.5% (n = 65) of gastric cancers. Cases with clear cell changes (GCC) were associated significantly with older age, intestinal type histology, body/fundic location, greater depth of invasion, lymph node metastases and lymphovascular invasion. An increasing proportion of clear cell changes indicated a worsening prognosis, and was identified as an independent marker of poor prognosis using the Cox proportional hazard model (hazard ratio, 0.462; P = 0.003). Of 62 GCCs subjected to special staining, 35 cases (55.6%) displayed cytoplasmic accumulation of glycogen, while 21 (33.3%) contained mucin. GCCs showing glycogen accumulation expressed AFP, glypican-3 and CD10 more commonly than those with mucin, which commonly expressed Muc5AC and Muc6. CONCLUSION: Clear cell gastric adenocarcinoma is a unique subgroup of gastric cancer which, although heterogeneous, has a poor prognosis.

Risk factors for delayed gastric emptying caused by anastomosis edema after subtotal gastrectomy for gastric cancer.

BACKGROUND/AIMS: Delayed gastric emptying (DGE) is one of the most troublesome complications after subtotal gastrectomy for gastric cancer. We evaluated operative and perioperative variables to assess for independent risk factors of DGE caused by anastomosis edema. METHODOLOGY: The study retrospectively reviewed clinical data of 382 consecutive patients who underwent subtotal gastrectomy for gastric cancer between 2009 and 2011 at a single institution. RESULTS: Delayed gastric emptying had occurred in twelve patients (3.1%). Univariate analysis revealed high body mass index (>25kg/m2), open gastrectomy, and Billroth II or Roux-en Y reconstructions to be significant factors for delayed gastric emptying. Multivariate analysis identified high body mass index and open gastrectomy as predictors of delayed gastric emptying. CONCLUSIONS: To avoid delayed gastric emptying, surgeons should take care in creating the gastrointestinal anastomosis, particularly in patients with high BMI or in cases of open gastrectomy.

Comparison between the mesenteric fixation method (MEFIX) and conventional methods at preventing the occurrence of Petersen's hernia: a study protocol for a multicenter randomized controlled trial.

BACKGROUND: Petersen's hernia, which occurs after Billroth-II (B-II) or Roux-en-Y (REY) anastomosis, can be reduced by defect closure. This study aims to compare the incidence of bowel obstruction above Clavien-Dindo classification grade III due to Petersen's hernia between the mesenteric fixation method and the conventional methods after laparoscopic or robotic gastrectomy. METHODS: This study was designed as prospective, single-blind, non-inferiority randomized controlled multicenter trial in Korea. Patients with histologically diagnosed gastric cancer of clinical stages I, II, or III who underwent B-II or REY anastomosis after laparoscopic or robotic gastrectomy are enrolled in this study. Participants who meet the inclusion criteria are randomly assigned to two groups: a CLOSURE group that underwent conventional Petersen's defect closure method and a MEFIX group that underwent the mesenteric fixation method. The primary endpoint is the number of patients who underwent surgery for bowel obstruction caused by Petersen's hernia within 3 years after laparoscopic or robotic gastrectomy. DISCUSSION: This trial is expected to provide high-level evidence showing that the MEFIX method can quickly and easily close Petersen's defect without increased postoperative complications compared to the conventional method. TRIAL REGISTRATION: ClinicalTrials.gov NCT05105360. Registered on November 3, 2021.

Cancer spheres from gastric cancer patients provide an ideal model system for cancer stem cell research.

Cancer stem cells have been hypothesized to drive the growth and metastasis of tumors. Because they need to be targeted for cancer treatment, they have been isolated from many solid cancers. However, cancer stem cells from primary human gastric cancer tissues have not been isolated as yet. For the isolation, we used two cell surface markers: the epithelial cell adhesion molecule (EpCAM) and CD44. When analyzed by flow cytometry, the EpCAM(+)/CD44(+) population accounts for 4.5% of tumor cells. EpCAM(+)/CD44(+) gastric cancer cells formed tumors in immunocompromised mice; however, EpCAM(-)/CD44(-), EpCAM(+)/CD44(-) and EpCAM(-)/CD44(+) cells failed to do so. Xenografts of EpCAM(+)/CD44(+) gastric cancer cells maintained a differentiated phenotype and reproduced the morphological and phenotypical heterogeneity of the original gastric tumor tissues. The tumorigenic subpopulation was serially passaged for several generations without significant phenotypic alterations. Moreover, EpCAM(+)/CD44(+), but not EpCAM(-)/CD44(-), EpCAM(+)/CD44(-) or EpCAM(-)/CD44(+) cells grew exponentially in vitro as cancer spheres in serum-free medium, maintaining the tumorigenicity. Interestingly, a single cancer stem cell generated a cancer sphere that contained various differentiated cells, supporting multi-potency and self-renewal of a cancer stem cell. EpCAM(+)/CD44(+) cells had greater resistance to anti-cancer drugs than other subpopulation cells. The above in vivo and in vitro results suggest that cancer stem cells, which are enriched in the EpCAM(+)/CD44(+) subpopulation of gastric cancer cells, provide an ideal model system for cancer stem cell research.

Actual 3-Year Survival After Reduced-Port Laparoscopic Distal Gastrectomy for Gastric Cancer (RpLDG): a Propensity Score Matching Analysis.

BACKGROUND: Total laparoscopic distal gastrectomy for early gastric cancer has been widely accepted; however, reduced-port laparoscopic distal gastrectomy has not gained the same popularity because of technical difficulties and oncologic safety issues. This study aimed to analyze the oncologic safety and short-term surgical outcomes of patients who underwent reduced-port laparoscopic distal gastrectomy (RpLDG) for gastric cancer. METHODS: Consecutive patients who underwent surgical treatment between January 2016 and May 2018 were included in this study. Of the 833 patients enrolled, 158 underwent RpLDG and were propensity-matched with 158 patients who underwent conventional port laparoscopic distal gastrectomy (CpLDG). The groups were compared in terms of short-term outcomes and disease-free and overall survival rates. RESULTS: The RpLDG group had shorter operation times (161.8 min vs. 189.0 min, p < 0.00) and shorter postoperative hospital stays (7.6 days vs. 9.1 days, p = 0.04) compared to the CpLDG group. Estimated blood loss was lower in the RpLDG group than in the CpLDG group (52.6 mL vs. 73.7 mL, p < 0.00), while hospital costs incurred by the RpLDG group were lower than those of the CpLDG group (10,033.7 vs. 11,016.8 USD, p < 0.00). No statistical differences were found regarding overall morbidity and occurrence of surgical complications of grade III or higher, as defined by the Clavien-Dindo classification. Furthermore, no significant differences between RpLDG and CpLDG were found in 3-year disease-free (99.4% vs. 98.1%; p = 0.42) and 3-year overall survival rates (98.7% vs. 96.8%; p = 0.25). CONCLUSION: Patients who underwent RpLDG had better short-term surgical outcomes than those who underwent CpLDG in terms of operation time, estimated blood loss, duration of hospital stay, and hospital costs. The oncologic safety of RpLDG was satisfactory.

Lymph node metastasis from intestinal-type early gastric cancer: experience in a single institution and reassessment of the extended criteria for endoscopic submucosal dissection.

BACKGROUND: Given the increasing use of endoscopic resection as a therapeutic modality for cases of early gastric cancer (EGC), it is very important to define strict criteria for the use of endoscopic mucosal resection and endoscopic submucosal dissection. To date, the criteria are almost entirely based on Japanese literature evaluating the risk of lymph node (LN) metastasis in patients with EGC. OBJECTIVE: To analyze our own experience with the factors affecting LN metastasis and to reappraise the extended criteria for endoscopic submucosal dissection. DESIGN: Retrospective, single-center study. SETTING: University teaching hospital. PATIENTS: This study involved 478 patients who underwent gastrectomy with LN dissection (n = 270, mucosal [m] EGC; n = 208, submucosal [sm] EGC). INTERVENTION: Gastrectomy with LN dissection. MAIN OUTCOME MEASUREMENTS: LN metastasis. RESULTS: Overall, 12.6% (60/478) of patients with EGCs presented with LN metastasis (mEGC, 3.0% [8/270], smEGC, 25.0% [52/208]). Increased size, macroscopic type (elevated), depth of invasion, and lymphovascular invasion were associated with LN metastasis. In 270 cases of mEGC, there was no relationship between clinicopathologic features and LN metastasis. In the smEGC group, size, depth of invasion, and lymphovascular emboli were associated with an increased risk of LN metastasis. Significantly, LN metastasis was noted in EGCs falling within established extended endoscopic submucosal dissection criteria, that is, intestinal-type mucosal cancer of any size without ulcer and no lymphovascular emboli (2/146 [1.4%]) or < or =3 cm with no lymphovascular emboli and irrespective of the presence of ulceration (2/126 [1.6%]) or intestinal-type submucosal cancer (sm1, <500 microm) without lymphovascular invasion and measuring < or =3 cm in size (3/20 [15.0%]). LIMITATIONS: Retrospective review of a single-center study. CONCLUSION: We recommend that more centers survey their experiences of LN metastasis in cases of EGC to refine the criteria for endoscopic submucosal dissection as a therapeutic modality of intestinal-type EGC.

Roux-en-Y gastrojejunostomy using modified hemi-double stapling.

For reconstruction after distal gastrectomy, the Roux-en-Y gastrojejunostomy is superior to the Billroth II gastrojejunostomy in terms of bile reflux. Roux-en-Y gastrojejunostomy prevents reflux gastritis, esophagitis, and carcinogenesis of the gastric remnant. However, the Roux-en-Y gastrojejunostomy is relatively complicated and lengthy. The authors perform a simple, safe Roux-en-Y gastrojejunostomy using modified hemi-double stapling. We applied this technique to 42 patients with gastric cancer. The average operating and reconstruction times were 172.6 +/- 42.0 and 26.2 +/- 4.8 min, respectively. The postoperative courses were uneventful and the patients were discharged 11.2 +/- 2.4 days postoperatively. Neither leakage nor bleeding from the gastrojejunostomy has occurred postoperatively. The postoperative follow-up was 7-24 months and no local recurrence or stricture at the gastrojejunostomy site occurred. Roux-en-Y gastrojejunostomy using the modified hemi-double stapling technique can achieve reconstruction more simply, safely and quickly, and may provide an alternative reconstruction method for distal gastrectomy.

Atraumatic Liver Retraction Using Nelaton Catheters During Totally Laparoscopic Gastrectomy.

This study introduces a novel technique for liver retraction during laparoscopic gastrectomy and assesses its impact on postoperative recovery. This study included 139 patients in whom Nelaton catheters (n=57) or Nathanson retractors (n=82) were used for liver retraction. Serum liver enzyme levels were measured preoperatively and on the first, second, third, fifth, and seventh postoperative days. Clinicopathologic features and postoperative recovery variables between the 2 groups were compared. The aspartate aminotransferase, alanine aminotransferase, and C-reactive protein levels were significantly lower (P<0.001, P<0.001, and P=0.007, respectively), and the day of first flatus, the day of initiating a soft diet, and the length of hospital stay were shorter in the Nelaton catheter U-shaped retractor group than those seen in the Nathanson retractor group (P=0.035, P=0.002, and P=0.024, respectively). Atraumatic liver retraction with Nelaton catheters is recommended in laparoscopic gastrectomy.

Epidemiologic Study of Human Epidermal Growth Factor Receptor 2 Expression in Advanced/Metastatic Gastric Cancer: an Assessment of Human Epidermal Growth Factor Receptor 2 Status in Tumor Tissue Samples of Gastric and Gastro-Esophageal Junction Cancer.

PURPOSE: The Trastuzumab for gastric cancer (GC) trial identified human epidermal growth factor receptor 2 (HER2) as a predictor of successful treatment with trastuzumab (HER2 receptor targeting agent) among patients with advanced/metastatic GC. To date, the prevalence of HER2 overexpression in the Korean population is unknown. The present study aimed to assess the incidence of HER2 positivity among GC and gastroesophageal (GE) junction cancer samples and the relationship between HER2 overexpression and clinicopathological characteristics in Korean patients. MATERIALS AND METHODS: Tumor samples collected from 1,695 patients with histologically proven GC or GE junction enrolled at 14 different hospitals in Korea were examined. After gathering clinicopathological data of all patients, HER2 status was assessed by immunohistochemistry (IHC) at each hospital, and IHC 2+ cases were subjected to silver-enhanced in situ hybridization at 3 central laboratories. RESULTS: A total of 182 specimens tested positive for HER2, whereas 1,505 tested negative. Therefore, the overall HER2-positive rate in this study was 10.8% (95% confidence interval=9.3%-12.3%). The HER2-positive rate was higher among intestinal-type cases (17.6%) than among other types, and was higher among patients older than 70 years and 50 years of age, compared to other age groups. CONCLUSIONS: Our evaluation of the HER2 positivity rate (10.8%) among Korean patients with GC and GE junction indicated the necessity of epidemiological data when conducting studies related to HER2 expression in GC and GE junction.

Duodenal stump fistula after gastrectomy for gastric cancer: risk factors, prevention, and management.

PURPOSE: A duodenal stump fistula is one of the most severe complications after gastrectomy for gastric cancer. We aimed to analyze the risk factors for this problem, and to identify the methods used for its prevention and management. METHODS: We retrospectively reviewed the clinical data of 716 consecutive patients who underwent curative gastrectomy with a duodenal stump for gastric cancer between 2008 and 2013. RESULTS: A duodenal stump fistula occurred in 16 patients (2.2%) and there were 2 deaths in this group. Univariate analysis revealed age >60 years (odds ratio [OR], 3.09; 95% confidence interval [CI], 0.99-9.66), multiple comorbidities (OR, 4.23; 95% CI, 1.50-11.92), clinical T stage (OR, 2.91; 95% CI, 1.045-8.10), and gastric outlet obstruction (OR, 8.64; 95% CI, 2.61-28.61) to be significant factors for developing a duodenal stump fistula. Multivariate analysis identified multiple comorbidities (OR, 3.92; 95% CI, 1.30-11.80) and gastric outlet obstruction (OR, 5.62; 95% CI, 1.45-21.71) as predictors of this complication. CONCLUSION: Multiple comorbidities and gastric outlet obstruction were the main risk factors for a duodenal stump fistula. Therefore, preventive methods and aggressive management should be applied for patients at high risk.

Risk of lymph node metastasis in mixed-type early gastric cancer determined by the extent of the poorly differentiated component.

AIM: To predict the rate of lymph node (LN) metastasis in diffuse- and mixed-type early gastric cancers (EGC) for guidelines of the treatment. METHODS: We reviewed 550 cases of EGC with diffuse- and mixed-type histology. We investigated the clinicopathological factors and histopathological components that influence the probability of LN metastasis, including sex, age, site, gross type, presence of ulceration, tumour size, depth of invasion, perineural invasion, lymphovascular invasion, and LN metastasis status. We reviewed all slides and estimated the proportions of each tumour component; pure diffuse type, mixed-predominantly diffuse type (diffuse > intestinal type), mixed-predominantly intestinal type (intestinal > diffuse type), and mixed diffuse = intestinal type. We calculated the extents of the respective components. RESULTS: LN metastasis was observed in 12.9% (71/550) of early gastric cancers cases [15/288 mucosal EGCs (5.2%) and 56/262 submucosal EGCs (21.4%)]. Of 550 cases, 302 were diffuse-type and 248 were mixed-type EGCs. Of 248 mixed-type EGCs, 163 were mixed-predominantly diffuse type, 82 were mixed-predominantly intestinal type, and 3 were mixed diffuse = intestinal type. Mixed-type cases with predominantly diffuse type histology showed a higher frequency of LN metastasis (20.2%) than cases of pure diffuse type (9.3%) and predominantly intestinal type (12.2%) histology. We measured the dimensions of each component (intestinal and diffuse type) to determine the association of the extent of each component with LN metastasis in mixed-type gastric carcinoma. The total tumour size and the extent of poorly differentiated components was associated with LN metastasis, while that of signet ring cell components was not. CONCLUSION: We recommend careful identification and quantitative evaluation of mixed-type early gastric cancer components after endoscopic resection to determine the intensity of the treatment.

Risk factors for lymph node metastasis in mucosal gastric cancer and re-evaluation of endoscopic submucosal dissection.

PURPOSE: The selection of the appropriate treatment strategy for patients with mucosal gastric cancer (MGC) remains controversial. In the present study, we aimed to determine the risk factors for lymph node (LN) metastasis in MGC and reassess the role of endoscopic submucosal dissection (ESD). METHODS: We examined 1,191 MGC patients who underwent curative gastrectomy between January 2005 and December 2014. We determined the clinicopathologic risk factors for LN metastasis among the MGC patients. RESULTS: Among 1,191 patients with MGC, 42 patients (3.5%) had LN metastasis. Univariate analysis indicated that age ≤ 50 years (P = 0.045), tumor invasion to the muscularis mucosa (P < 0.001), tumor size > 2 cm (P = 0.014), presence of ulceration (P = 0.01), diffuse type as per Lauren classification (P = 0.005), and undifferentiated-type histology (P = 0.001) were associated with LN metastasis. Moreover, multivariate analysis indicated that tumor invasion to the muscularis mucosa (P = 0.001; odds ratio [OR], 4.909), presence of ulceration (P = 0.036; OR, 1.982), and undifferentiated-type histology (P = 0.025; OR, 4.233) were independent risk factors for LN metastasis. In particular, LN metastasis was observed in some MGC cases with indications for ESD, including absolute indications (1 of 179, 0.6%) and expanded indications (9 of 493, 1.8%). CONCLUSION: Although MGC patients can be treated via ESD, we recommend that they undergo a more aggressive treatment strategy if they have tumor invasion to the muscularis mucosa, ulceration, or undifferentiated-type histology in the final pathology report.

Effect of extramucin pools in gastric cancer patients.

PURPOSE: Mucinous gastric adenocarcinoma (MGC) is defined by the World Health Organization as a gastric adenocarcinoma with >50% extracellular mucin pools within the tumors. In this study, we attempted to analyze the clinicopathologic features of patients pathologically diagnosed as gastric cancer with lower than 50% tumor volume of extracellular mucin pool adenocarcinoma (LEMPC). We compared MGC versus nonmucinous gastric adenocarcinoma (NMGC). We were used in abbreviations LEMPC for NMGC including extracellular mucin pool. METHODS: Files of 995 patients with gastric cancer NMGC (n = 935), MGC (n = 20), LEMPC (n = 40) who underwent curative resection at Pusan National University Yangsan Hospital from December 2008 to December 2013 were retrospectively analyzed. All pathologic reports after curative resection and evaluated clinicopathologic features were reviewed to identify the effect of extracellular mucin pools in gastric cancer. RESULTS: Compared with the NMGC patients, the clinicopathological features of MGC patients were as follows: more frequent open surgery, larger tumor size, more advanced T stage and N stage, more positive lymph node metastasis, and perineural invasion. LEMPC patients showed similar features compared with NMGC patients. MGC and LEMPC patients showed similar clinicopathological features, except T stage and lymph node metastasis. CONCLUSION: LEMPC can be thought of as a previous step of MGC. It is reasonable to consider LEMPC patients in the diagnostic criteria of MGC, and to adequately treat.

Unveiling lymph node metastasis in early gastric cancer.

With respect to gastric cancer treatment, improvements in endoscopic techniques and novel therapeutic modalities [such as endoscopic mucosal resection (EMR) and endoscopic submucosal dissection (ESD)] have been developed. Currently, EMR/ESD procedures are widely accepted treatment modalities for early gastric cancer (EGC). These procedures are most widely accepted in Asia, including in Korea and Japan. In the present era of endoscopic resection, accurate prediction of lymph node (LN) metastasis is a critical component of selecting suitable patients for EMR/ESD. Generally, indications for EMR/ESD are based on large Japanese datasets, which indicate that there is almost no risk of LN metastasis in the subgroup of EGC cases. However, there is some controversy among investigators regarding the validity of these criteria. Further, there are currently no accurate methods to predict LN metastasis in gastric cancer (for example, radiologic methods or methods based on molecular biomarkers). We recommend the use of a 2-step method for the management of early gastric cancer using endoscopic resection. The first step is the selection of suitable patients for endoscopic resection, based on endoscopic and histopathologic findings. After endoscopic resection, additional surgical intervention could be determined on the basis of a comprehensive review of the endoscopic mucosal resection/endoscopic submucosal dissection specimen, including lymphovascular tumor emboli, tumor size, histologic type, and depth of invasion. However, evaluation of clinical application data is essential for validating this recommendation. Moreover, gastroenterologists, surgeons, and pathologists should closely collaborate and communicate during these decision-making processes.

Solitary peritoneal lymph node metastasis of head and neck cancer diagnosed with FDG-PET/CT imaging.

Distant metastasis of head and neck squamous cell carcinoma (SCC) to the infraclavicular lymph nodes-with the exception of the upper mediastinal lymph nodes-is rare. We report the case of a 44-year-old man who was treated with surgery and radiotherapy for SCC of the floor of the mouth. During regular follow-up 6 months after the cessation of radiotherapy, F18-fluorodeoxyglucose positron-emission tomography/computed tomography (FDG-PET/CT) detected a hypermetabolic lesion in the left lobe of the liver that was diagnosed as a metastasis of the head and neck SCC; no locoregional recurrence was found. The metastasis was surgically removed and more radiotherapy was administered, but the SCC recurred at the same site and the patient died of disseminated disease 12 months after the appearance of the first metastasis. To the best of our knowledge, this is the first reported case of a solitary peritoneal lymph node metastasis from an SCC of the floor of the mouth. We believe that regular FDG-PET/CT follow-up scans are useful for the detection of unusual distant metastases of head and neck cancers.

Pathologic definition and number of lymphovascular emboli: impact on lymph node metastasis in endoscopically resected early gastric cancer.

Endoscopic submucosal dissection (ESD) is widely accepted as an appropriate treatment modality for early gastric cancer (EGC). Accepted indications for ESD are mostly based on the risk of lymph node (LN) metastasis in EGC. The presence of lymphovascular emboli (LVEs) is the most important risk factor for predicting LN metastasis, but the criteria for diagnosing LVEs are inconsistent and controversial. Here, we defined LVE as the presence of tumor cells within a space according to the following criteria: (1) red cells or lymphocytes surrounding the tumor cells, (2) an endothelial cell lining, and (3) attachment to the vascular wall. We reviewed a series of 102 patients with EGC who underwent gastrectomy after ESD, evaluated the definition of LVE, counted the number of LVEs in ESD specimens, and validated the significance of the definition and number of LVEs with regard to the presence of LN metastasis in gastrectomy specimens using receiver operating characteristic (ROC) curve analysis. Overall, 13 instances (12.7%) of LN metastasis were identified among 102 patients with EGC who underwent gastrectomy after ESD. The LN metastasis-positive group showed higher numbers of definite (4.46 ± 2.45 versus 0.19 ± 0.07), suspicious (3.15 ± 0.76 versus 0.62 ± 0.14), and probable (1.62 ± 0.43 versus 0.43 ± 0.10) LVEs in ESD specimens than the LN metastasis-negative group. In ROC analysis, the area under the ROC curve was 0.851 (95% confidence interval [CI], 0.711-0.991) for definite LVEs, compared with 0.82 (95% CI, 0.698-0.960) for suspicious LVEs and 0.72 (95% CI, 0.549-0.891) for probable LVEs. We recommend the use of strict LVE criteria to predict LN metastasis and determine the need for surgical intervention after ESD.

Mucin expression in gastric cancer: reappraisal of its clinicopathologic and prognostic significance.

CONTEXT: The clinical validity of mucin expression in gastric cancer is debated. Whereas several reports demonstrate a correlation between mucin expression and prognosis, others deny such an association. OBJECTIVES: This survival analysis study aims to elucidate the prognostic significance of mucin expression in gastric cancer. DESIGN: A retrospective survival analysis was done with 412 cases of gastric cancer characterized on the basis of MUC immunohistochemistry using MUC2, MUC5AC, MUC6, and CD10 antibodies; the cases were divided into those with a gastric, an intestinal, or a null mucin phenotype based on the predominant mucin. RESULTS: There was no association between mucin expression and survival when considering overall gastric cancers or the advanced gastric cancer subtype. However, early gastric cancers with a gastric mucin phenotype showed longer survival than those with an intestinal mucin phenotype (P = .01) or a null phenotype (P = .01). In particular, MUC5AC-positive early gastric cancers resulted in longer survival than did those that did not express MUC5AC (P = .009). The loss of MUC5AC expression was identified as an independent, poor prognostic factor in early gastric cancers using the Cox regression proportional hazard model (hazard ratio, 3.50; P = .045). CONCLUSIONS: MUC5AC expression is significantly associated with patient survival and can be used to predict outcomes in the gastric cancers, especially in the early gastric cancers.

Lymph node metastasis in early gastric cancer: evaluation of a novel method for measuring submucosal invasion and development of a nodal predicting index.

After endoscopic resection of early gastric cancer (EGC), it is imperative to accurately determine whether follow-up surgery is indicated, since this technique is used as a first line of treatment. Herein, we developed a scoring system to indicate the risk of lymph node metastasis in submucosal EGC (smEGC), and present a novel method to measure depth of submucosal invasion. In our series, 15.9% of the smEGC presented with lymph node metastasis. A nodal prediction index, based on the variables extracted from the univariate analysis and defined as nodal prediction index = (2.128 × lymphovascular tumor emboli) + (1.083 × submucosal invasion width ≥ 0.75 cm) + (0.507 × submucosal invasion depth ≥ 1000 µm) + (0.515 × infiltrative growth pattern), yielded an area under the receiver operating characteristic curve of 0.809 (P =.000, 95% CI = 0.713-0.096) in a training group, and showed comparable result in validation group (0.886, P =.000, 95% CI = 0.796-0.977). Depth of invasion was statistically higher in the metastatic group when measured from the lowest point of an imaginary line in continuity with the adjacent muscularis mucosa to the point of deepest tumor penetration, but not when using the classic measurement method. The area under the receiver operating characteristic curve of the alternative measurement method was 0.652 (P =.013, 95% CI = 0.550-0.754) compared to 0.620 for the classic measurement method (P =.0480, 95% CI = 0.509-0.731). In deciding whether surgery is indicated after endoscopic submucosal dissection for smEGCs, we recommend to test our alternative method of measuring submucosal invasion and to evaluate our nodal prediction index as an adjunct tool.